$T$ -odd parton distribution functions and azimuthal anisotropy at high transverse momentum in $p\text{−}p$ and $p\text{−}A$ collisions

Journal Article · 03 February 2025 · Physical Review. C

DOI: https://doi.org/10.1103/PhysRevC.111.024901 · OSTI ID:2510937

Soudi, Ismail ; Majumder, Abhijit

Various azimuthal anisotropies ( $v_1,v_2,v_3,v_4$ ), at high transverse momentum (high $p_T$ ), are shown to arise from the asymmetric scattering of transverse polarized quarks and gluons, arising from unpolarized nucleons (the Boer-Mulders effect) and resulting in unpolarized hadrons (the Collins effect). Combined with the asymmetric scattering of partons from polarization independent but transverse momentum dependent (TMD) distributions, we obtain a possible mechanism to understand the azimuthal anisotropy of hadrons at large transverse momentum observed in $p\text{−}p$ collisions. Constraining the ratio of polarization dependent TMD distributions to polarization independent distributions by comparing with the data from $p\text{−}p$ collisions, we find that scaling the acquired transverse momentum of the initial state partons from the proton, due to prescattering before the hard interaction, with the length of the nucleus ( $k_{\perp }^2\propto A^{1/3}$ ), straightforwardly yields the azimuthal anisotropy at high $p_T$ in $p\text{−}A$ collisions. Published by the American Physical Society 2025

• Sponsoring Organization: USDOE
• Grant/Contract Number: SC0013460
• OSTI ID: 2510937
• Journal Information: Physical Review. C, Journal Name: Physical Review. C Journal Issue: 2 Vol. 111; ISSN PRVCAN; ISSN 2469-9985
• Publisher: American Physical SocietyCopyright Statement
• Country of Publication: United States
• Language: English